Yeah, Arthur Whitney's code is extreme (he is one of a kind) but the sentiment is something i wholeheartedly subscribe to.

The key point is this; once you've sufficiently studied that screen or two of code, you can understand all of it at the same time. If it's spread out over thousands of files, it's very difficult to understand all of it,

Because there are so many interlocking concepts in code you have to keep as much as possible in your head to build up the entire picture. This is where concise, terse and direct-to-the-point code shines; nothing gets in the way of putting all the pieces of the jigsaw puzzle in front of you so you can "get" everything at a glance. A good example is K&R C style espoused in their book which i used to find difficult in the beginning but now understand. Always put as much of relevant code as possible into one screenful.